1. Field of the Invention
This invention relates to a method and apparatus for marking an object by imprinting characters onto the surface of the object and more particularly to a method and apparatus for simultaneously forming a plurality of characters on the surface of an object by simultaneously imprinting indented dot portions of the selected characters to thus simultaneously form the plurality of characters.
2. Description of the Prior Art
U.S. Pat. No. 4,506,999 discloses apparatus for forming multi-character messages by striking the surface of an object with a plurality of marking pins. The pins are mounted in a head or housing and are selectively actuated to form portions of a single character and as the object is moved relative to the housing, additional characters are formed by the same pins. Programmable controls are disclosed to provide the desired sequence of characters.
U.S. Pat. No. 4,214,520 discloses an imprint marking device that includes a plurality of marking elements or characters carried on the peripheral surface of a marking wheel. The wheel is rotated to the selected character and is advanced into marking relation with the surface of the object. The marking device with the wheel is then moved laterally relative to the object and the wheel is rotated to another preselected character and is again moved against the surface of the object to form a sequential mark.
British Patent No. 2,002,694 discloses a programmable dot matrix type of engraver for impressing a selected size of alpha-numeric characters on a work piece. The engraver is computer controlled to provide selective continuous marking of the work piece. The engraving tool is supported on an arm which is movable on a carriage by a lead screw rotated by a stepping motor. The carriage is movably mounted on a horizontal arm which is in turn supported by a vertical column above a base on which the object to be marked is fixedly positioned. With this arrangement, the engraving tool is movable along the horizontal x axis and stepped vertically or at a 90.degree. angle along the y axis. The engraving tool has a punch which is remotely controlled by control means to form the desired dot matrix character. The size of the character engraved is determined by the number of steps of the stepping motor between each point on the 7.times.5 matrix. The engraver is arranged to form all of the indentations for all of the characters along the first x=1 axis and is then stepped to the second y=2 axis. The punch then moves along the y=2 axis and forms the indentations along the y=2 axis for all of the characters. Thus it is necessary for the punch to travel the entire length of the x axis for all characters for each step of the y axis. In this manner, all of the characters are formed by sequential stepping of the punch along the y axis and raster movement along the x axis.
U.S. Pat. No. 3,814,227 discloses a printer using a matrix of printing elements that are arranged in a square configuration with the printing elements arranged to print alpha-numeric data in either a vertical or horizontal orientation by selecting a rectangular matrix from less than the full number of printing elements in the square matrix to permit selectively orientation of the printed data without mechanically reorienting the head. The printing matrix may print from either end of a selected rectangular print matrix in either a horizontal or vertical orientation to provide four possible orientations of the printed alpha-numeric data.
U.S. Pat. No. 4,428,692 discloses a high speed impact matrix printer for use with data processing systems and digital communication systems. The printer is a wire matrix printer with the print head having wires arranged as a column within a wire guide. The print head is stepped serially across a print record and the print wire drivers fire the print wires in accordance with character configuration information.
U.S. Pat. Nos. 4,591,279 and 4,652,156 disclose improved print type impact printers with the apparatus for moving the print head relative to the object to be marked to form the desired characters by forming dot type indentations in the surface of the object.
U.S. Pat. No. 4,848,942 discloses pin type marking devices for marking an arcuate surface with dot matrix characters.
Certain of the above prior art printers and engravers utilize the pins to form a single character and then progress, usually horizontally, to form a second character on the object being marked. Other prior art engravers sequentially form portions of each character and thereafter, in a "raster" type pattern, sequentially form other portions of all of the characters until all of the characters are formed. There is a need for an impact type printer which will simultaneously and separately form a plurality of characters with a plurality of pins and also selectively form characters of different dimensions.